不同叶轮形式下离心泵噪声特性对比研究

Comparison of noise characteristics in centrifugal pumps with different types of impellers

针对具有无短叶片和有短叶片两种叶轮形式的离心泵,对设计状态下离心泵内部流场进行了全三维、非定常数值模拟,对比分析了其非定常流场特性和噪声辐射特性。流场分析表明:叶轮叶片和蜗舌的相互作用造成了叶片表面强烈的压力脉动,对长短叶片的叶轮形式,在局部增加长叶片表面压力脉动的同时,短叶片表面的压力脉动保持较低水平;同时能够有效降低泵体进口压力脉动,但出口压力脉动有所增强。以叶轮叶片表面作为声源辐射面,对比分析了两种叶轮的偶极子噪声辐射特性,结果表明:长短叶片结构通过改变声能在频域上的分布,从而能有效降低总声压级。

For impellers without splitter blades and with splitter blades, the unsteady computational fluid dynamics method, large eddy simulation （LES）, is applied to study the whole three dimensional flow field in centrifugal pumps, and the characteristics of flow field and noise are analyzed and compared. It has been shown that the interaction between impeller blades and volute tongue induces strong pressure fluctuations on blade surfaces. For impeller with splitter blades, although some local pressure fluctuations on main blade surfaces are increased, the pressure fluctuations on splitter blade surfaces remain at a lower level. At the same time, the pressure fluctuations on the pump inlet surface are decreased effectively, but the pressure fluctuations on the outlet surface are enlarged. Taken the blade surfaces as radiant resources, the noise features of dipole for the two types of impellers are compared. It is the splitter blades that change the distribution of acoustic energy in frequency domain, thus the OASPL is effectively reduced.